#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;
int n,m,ans=0,l[100010],r[100010],a[100010];
bool flag[100010];
void dfs(int k,int sum)
{
	if (k>n)
	{
		if (sum>ans) ans=sum;
		return;
	}
	dfs(k+1,sum);
	for (int i=1;i<=m;i++)
		if (!flag[i]&&a[k]>=l[i]&&a[k]<=r[i])
		{
			flag[i]=1;
			dfs(k+1,sum+1);
			flag[i]=0;
		}
}
int main()
{
	freopen("bg.in","r",stdin);
	freopen("bg.out","w",stdout);
	ios::sync_with_stdio(false);
	cin>>n>>m;
	for (int i=1;i<=n;i++)
		cin>>a[i];
	for (int i=1;i<=n;i++)
		cin>>l[i]>>r[i];
	dfs(1,0);
	cout<<ans<<endl;
	fclose(stdin);
	fclose(stdout);
	return 0;
}